While it was originally produced by Kauffmann, the famous K55K 'Black Cat' has been most famously produced by Mercator. While other German firms have made exact copies, the Boker Plus Atlas doesn't have a lot in common with it, in my opinion. Unlike the Cognet series of knives, for example, or Cold Steel's Pocket Bushman, the spring isn't enclosed. Then there's the blade, it's the same polished drop-point blade that Boker Plus use on some of their other knives (the Tech Tool series for example, which have synthetic or wooden covers), and it has the same hollow-grind, whereas the Mercator is a Spear-point blade, with a flat grind. The blade is stainless rather than carbon-steel, and at 2.64", it's nearly an inch shorter than the Mercator blade, and a substantially smaller knife all-round. Unlike the Mercator, the Atlas doesn't lock, and it doesn't have a bail either. It's made of copper, and the handle isn't actually a folded sheet of metal; as you noted, the spring is exposed, and the stainless spring runs the full length of the handle, forming a butt plate, with a lanyard hole. The Atlas also has that large pivot pin of course, and (sadly), Boker felt the need to add a (thankfully removeable) pocket-clip. The knife is also available with scissors, I think if Boker had wanted to produce a Mercator 'knock-off', they could have probably produced something with more in common, like the German-made K55K clone below for example. I like drop-point blades, and we don't see a lot of them on folders, so I'm glad they went with this blade, rather than copying the Mercator's spear-point.